Definition - What does Non-Admitted Insurer mean?
A non-admitted insurer is an insurance company that is not licensed to underwrite risks in a given territory.
Non-admitted insurers are still allowed to sell insurance policies in the territory in question. This allows them to issue policies that admitted insurers cannot, but may also come with less security.
Insuranceopedia explains Non-Admitted Insurer
The insurance industry is highly regulated, with licensing schemes, enforced best practices, and a number of other mechanisms to ensure that insurance products are secure investments and that policyholders are treated fairly. Insurers who have not be officially authorized to work in a given territory, however, don't have to follow these industry regulations, which means they can issue riskier policies and take on policyholders that admitted insurance companies deem too risky to insure.
Purchasing a policy from a non-admitted insurer can be riskier, but that is not always the case. Consulting industry ratings, for instance, could reveal that an admitted insurer is in worse standing than a non-admitted insurer.